الفهرس 
General introductionOnly 14 pages are availabe for public view
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Abstract
Activated carbon, silica nanoparticles, and N-halamine polymers have been prepared from different types of agricultural wastes with different treatments. Activated carbon prepared from treated sawdust (SAC) with H3PO4 and carbon dioxide evolved from calcium carbonate while silica nanoparticles were prepared from rice husks through chemical and biosynthesis methods and N-halamine polymers were prepared from rice straw and depithed bagasse. The prepared SAC, functionalized Si-NPs#2-APTEs, and Si-NPs#1-APTEs/SAC composite were successfully characterized using different analytical tools as IR, SEM, TEM, and EDX analyses. The prepared samples have achieved the maximum ability to adsorb Pb(II), Co(II), and Cd(II) ions from aqueous media. The effect of different variables such as pH, contact time, initial metal ions concentration, and temperature influenced the adsorptive quantity was examined. from these results, it can be concluded that:
Optimum pH for maximum adsorption of Pb(II), Co(II), and Cd(II) for SAC, Si-NPs#2-APTEs, and Si-NPs#1-APTEs/SAC adsorbents were 6, 5.5, and 6, respectively.
The optimum contact time for equilibrium to be achieved was found to be 90, 60, 45 min for SAC, Si-NPs#2-APTEs, and Si-NPs#1-APTEs/SAC, respectively. It is basically due to saturation of the active sites which does not allow further adsorption to take place after this period.
It can be seen that by increasing the concentration of metal ions, the active adsorption sites become occupied with Pb(II), Co(II), and Cd(II), and the surface area was limited.
The adsorption rates for Pb(II), Co(II), and Cd(II) ions have been increased with increasing the temperature which indicates that the adsorption is an endothermic process. The uptakes of SAC, Si-NPs#2-APTEs, and Si-NPs#1-APTEs/SAC adsorbents for Pb(II), Co(II), and Cd(II) were increased with increasing the temperature. This may due to that the increase in temperature increases the adsorptive forces between the adsorbate and the active sites on the adsorbent surface and the rise of the ionization of the functional groups (sorption active sites) which increases their activity towards the sorption of from the medium with increasing temperature.
The experimental data of Pb(II), Co(II), and Cd(II) are well fitted to Langmuir more than
Chapter IV Summary and conclusion
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Freundlich model for three adsorbents and the maximum adsorptive quantities of Pb(II), Co(II), and Cd(II) were 48.83, 15.51, 12.39 mg/g for SAC, 15.93, 10.61, 9.69 mg/g for Si-NPs#2-APTEs, and 19.33, 11.03, 10.02 mg/g for Si-NPs#1-APTEs/SAC, respectively. The adsorption kinetic of Pb(II), Co(II), and Cd(II) obeys pseudo-second-order kinetic.
Furthermore, the prepared SAC, Si-NPs#2-APTEs, and Si-NPs#1-APTEs/SAC were tested for their ability to eliminate Pb(II), Co(II), and Cd(II) ions from the surface water and groundwater. In addition, studying the possibility to treat industrial wastewater (methylene blue and congo red) and trihalomethanes (THMs). The results of different experiments showed that SAC, Si-NPs#2-APTEs, and Si-NPs#1-APTEs/SAC have the ability to remove metal ions, methylene blue, congo red, and THMs, and it can be concluded that:
SAC has demonstrated a good ability to remove metal ions, but its ability to eliminate metal ions in surface water is often greater than that of groundwater. The results showed that the produced SAC had a higher tendency for adsorption removal of methylene blue than it did of Congo red. Similarly, the results showed that SAC was a successful material for removing THMs from aqueous media, implying that SAC has a high ability to eliminate DBPs from drinking water, particularly THMs.
Both Si-NPs#2-APTEs, and Si-NPs#1-APTEs/SAC have the ability to remove metal ions, methylene blue, Congo red, and trihalomethanes but with lower capacity than that of SAC. In addition, a Si-NPs#1-APTEs/SAC composite is showing better results in metal ions, methylene blue, Congo red, and trihalomethanes removal than that of Si-NPs#2-APTEs.
The antimicrobial activity of the prepared Si-NPs#1-APTEs, Si-NPs#3-APTEs, and Si-NPs#3 was evaluated against E. coli and S. aureus bacteria. Si-NPs#1-APTEs showed no antibacterial activity against E. coli and S. aureus bacteria while Si-NPs#2-APTEs, and Si-NPs#3 showed excellent antimicrobial activity against two models of bacteria. The bacteriostatic rates of Si-NPs#2-APTEs against E. coli and S. aureus reached up to 79.17% and 75.42%, while antimicrobial rates Si-NPs#3 against E. coli and S. aureus reached up to 86.65% and 82.54% which showed that the antibacterial efficiency of biosynthesized Si-NPs#3 was higher than Si-NPs#2-APTEs which prepared through chemical route.
Chapter IV Summary and conclusion
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N-halamine polymers have been prepared from rice straw, and depithed bagasse. N-halamine polymers are able to control the bacterial growth E. coli and S. aureus. During this study the effect of N-halamine polymers on the inhibition of both gram negative and gram-positive bacteria was investigated. Moreover, synthesis N-halamine/ silica nano composite is to improve the antimicrobial activity of N-halamine-based materials by enhancing surface area when silica nanoparticles incorporated into the N-halamine matrix because of its large surface area. For this purpose, N-HRSC, N-HDBC, N-HRSC/Si-NPs#3, and N-HDBC/Si-NPs#3 polymers were prepared followed by chlorination and the following results were recorded:
It was found that N-HRSC, and N-HDBC have succeeded in inhibiting the growth of E. coli and S. aureus giving the inhibition zone with an average diameter of 20.2 mm, 18.2 mm for N-HRSC, and 17.3 mm, 16.2 mm N-HDBC, respectively. The bacteriostatic rates of N-HRSC, and N-HRSC samples reached up to 96% and 94.5%, respectively, against E. coli and 94 and 91.4% against S. aureus after 240 min.
The composites N-HRSC/Si-NPs#3, and N-HDBC/Si-NPs#3 have increased the bacteriostatic rates to 100% for both composites against E. coli after 180 min, and 100% and 99.9% for N-HRSC/Si-NPs#3, and N-HDBC/Si-NPs#3, respectively, against the S. aureus after 180 min.
It was found that the incorporation Si-NPs inside N-halamine polymers enhance its antimicrobial activity. Moreover, N-HRSC/Si-NPs#3, and N-HDBC/Si-NPs#3 composites achieved the complete inhibition in short time compared with N-HRSC, and N-HDBC